Field of the Invention
The present disclosure relates generally to respiratory therapy systems. In particular, the present disclosure relates to patient interfaces, such as mask assemblies and breathing circuits, with condensation reducing or compensating configurations.
Description of the Related Art
CPAP therapy, commonly used to treat obstructive sleep apnea, pumps air to a patient to maintain a minimum pressure in the airways. Often the air is heated and humidified before being sent to the patient. This causes less dryness and irritation to the patient and can increase compliance in the therapy. An issue with humidified air is that it can condense into water, becoming rainout. This is due to the heated air cooling down and the air reaches a dew point, causing condensation.
Rainout can cause several problems, including the following: the water can restrict airflow to the patient or out of the mask; water can form into droplets and drip on a patients face which can wake them; a whistling noise can result when water forms on the vent holes; water can disrupt the mask seal against the patient's face; the patient may wake with a wet face which can feel unpleasant.
If a patient is unhappy with the rainout in their mask, they may reduce the humidification settings in their CPAP or turn off humidification entirely. Other advice to reduce rainout is to increase the temperature of the bedroom so that there is a smaller temperature drop between the humidified air and the ambient air of the room and thus less water will condense.